Write a Python program that reads a text file. The program should:

1. Extract all words and convert them to lowercase.

2. Store the words in a list.

3. Use a dictionary to group the words by their length.

4. Print all words that have the maximum length, in alphabetical order.

In the realm of artificial intelligence, machines learn from data.

Extraordinary algorithms power systems that simulate human cognition.

Sometimes, simplicity outperforms complexity.

Example of code execution:

Enter the filename: text2.txt

Words with the maximum length (13):

extraordinary

intelligence,